1. Field of the Invention
The invention relates to a device for detecting certain states of movement of the body of a user and for generating signals corresponding to the result of the detection for subsequent processing in a data processing system, and utilizes a bearing device for the body of the user, which device includes a support unit which is mounted in a tiltable manner on a base part and has a support surface for supporting the body of the user, and a sensor device for detecting the direction and the magnitude of the position of the projection of the body""s center of gravity into the support surface relative to a predetermined original position in the support surface from the direction and the magnitude of a tilt of the support surface and for generating corresponding sensor signals.
2. Discussion of Background Information
Generally known devices for detecting certain states of movement of a user are designed to be operated by hand (e.g. mouse, joystick or trackball) or by foot (see, for example, DE 43 36 153 C1 or DE 44 45 861 A1) and simply require the motoricity of individual extremities. This is of advantage when operating a data processing system with a conventional visual display unit in so far as the user is thus able to keep his head still and fix his eyes on the screen of the visual display unit.
However where certain applications are concerned, for example in the case of computer games or computer-aided design (CAD), visual output will in future take place to an increasing degree via visual display units which are secured to the user""s head, fill his entire field of vision, detect the movements of the user""s head and adapt the screen display to the detected head movements (so-called cyber-helmets). The purpose of this technology is to give the user the impression that he is in a virtual space (cyberspace) and thus create the illusion of virtual reality.
However the user of cyber-helmets of this kind no longer has to adopt a certain posture relative to the visual display unit. The impression of virtual reality is more likely to suffer if locomotion in this virtual space cannot be controlled by corresponding real movements of the legs and of the body of the user. Particularly unsatisfactory solutions are those which employ so-called cyber-gloves to detect hand or arm movements in order to control not just manual actions in virtual space, but also locomotion in this virtual space by, for example, indicating the desired direction.
A great many devices have therefore been proposed in the prior art which are able to detect movements of the legs and the body of the user and provide corresponding detection signals for subsequent processing in a data processing system, for example a personal computer. A device of this kind is known from WO-A-96/06664. In this device a support surface for supporting the body of the user is mounted in a tiltable manner on a base plate by a universal joint, which prevents the support surface from turning about a vertical axis. A conventional joystick, to the operating lever of which a ball is secured, is disposed at some distance from the universal joint. The ball is held in a sliding manner in a shaft which is connected to the support surface, so that, by using the joystick, shifts of the center of gravity of the user can be detected on the basis of the resulting tilting of the support surface. However this known device is restricted to detecting two degrees of freedom of movement, for example direction and magnitude of the shift of the center of gravity.
U.S. Pat. No. 4,817,950, U.S. Pat. No. 4,488,017, U.S. Pat. No. 5,405,152, WO-A-96/35494, EP-A-0 761 266 and U.S. Pat. No. 5,409,226 disclose further known devices which, like the device according to WO-A-96/06664, serve to detect only just two degrees of freedom of a shift of the center of gravity of the user, although in each case different mounting and sensor mechanisms are used.
The device known from WO-A-96/35494 differs from the other devices of the prior art in particular by the interpretation of the sensor signals at the subsequent data processing stage.
The devices described in U.S. Pat. No. 5,405,152 and U.S. Pat. No. 4,509,226 are not only formed as a sensor device for detecting the shift of the center of gravity of the user, but also comprise actuating devices which enable the user to be physically informed of changing boundary conditions of the computer simulation, for example a change from flat to hilly terrain, reactions of the computer simulation to his movements, etc.
WO-A-96/36955 discloses a device which enables the user to execute actual walking movements and, according to the deviation of the user, due to the walking, from a predetermined original position, actuating devices provided in the support surface are operated such that the user is returned to the predetermined original position, in spite of the walking movement.
GB-A-2 038 597 discloses a device of a similar type in which just one degree of freedom of the movement of the user, for example a rotation about a vertical axis, is detected and converted into a corresponding signal.
Since the known devices discussed above only enable two degrees of freedom to be detected, or even just one in the case of GB-A-2 038 597, quite a number of types of movement, for example jumps, have to be input manually, for example by pressing a button, which affects the impression of virtual reality.
The invention provides a device of the type initially mentioned which enables the user""s impression of virtual reality to be reinforced.
The invention provides for a device of which has a support surface mounted on a base part such that it can also rotate about a substantially vertical axis or/and move in the direction of a substantially vertical axis, and that a sensor device is also formed to detect the direction and the magnitude of a rotational movement of the body of the user about the substantially vertical axis and/or to detect at least the magnitude of a vertical movement of the body""s center of gravity, as well as to generate corresponding sensor signals. The unit according to the invention, is called xe2x80x9cCYBERSURFERxe2x80x9d by the applicants, and enables not just shifts of the body weight of the user to be detected and used to control locomotion in virtual space, but also rotational and vertical movements of the user. This is of particular interest in connection with computer games in which it is possible to simulate branches of sports such as surfing, snowboarding or skate-boarding or in which the virtual body of the user has to jump over virtual obstacles such as streams, gorges, etc. or climb rock faces, etc.
The user generally stands on the CYBERSURFER, so that he does not in fact have to move from a spot in real space in order to control his locomotion in virtual space. This is important in so far asxe2x80x94because he takes in his entire field of vision through the cyber-helmetxe2x80x94the user is blind to his real environment and therefore could not move safely in the latter. However the device according to the invention can in effect reinforce the user""s impression of virtual reality without endangering his safety in the process.
The support surface may, for example, be provided at a standing plate, preferably of relatively large dimensions, of the support unit of the bearing device. However it is also possible to provide two relatively small rest surfaces, disposed at a common connecting tube or similar device for supporting the user""s two feet. The provision of a relatively large support surface is advantageous in so far as it can also be used to sit or kneel on.
The support part is formed by the standing plate, the rest surfaces-connecting tube unit or similar device can be connected to an intermediate part, which is disposed between the base part and the support part, such that it tilts with this intermediate part, yet it is also allowed to turn relative to it. The intermediate part is in this case is preferably connected to a base part in a rotationally rigid manner.
The support unit may be mounted with the base part such that it can tilt and rotate about the substantially vertical axis by a ball-and-socket joint. The ball-and-socket joint can in this case be provided at a tubular section which is telescopically guided at a further tubular section secured to the base part. Such a design allows for four degrees of freedom of movement which can be detected according to the invention. Moreover, this freedom of movement is achieved with a simple and yet mechanically rugged construction.
The sensor device can be protected against unintentional damage by being disposed at least partly in a holding space defined by the tubular section, the further tubular section and the base part. Another possible way to protect the sensor device lies in disposing it in a protective housing which is formed and dimensioned such that it strikes against the tubular section and/or the further tubular section before the sensor device is deformed to excess. A further advantage in this case lies in the fact that the sensor device is disposed in the extension of the rotational axis, so that a rotational movement of the user can be detected undistorted, i.e. also as a turning movement of the sensor device, which facilitates subsequent interpretation of the detection signals.
The sensor device may, for example, be constructed and disposed at the CYBERSURFER such that a first part of the sensor device is secured to the base part and a second part of the sensor device is connected to a part of the ball-and-socket joint which is fixed to the support unit so as to tilt and rotate with it and, when the part of the ball-and-socket joint which is fixed to the support unit moves downwards relative to the second part of the sensor device, can be brought into pulling engagement with this. It is thus possible to use any suitable type of sensor device with the CYBERSURFER according to the invention, for example sensor devices comprising potentiometers, strain gauges, etc. However, with regard to a low susceptibility to wear, the invention proposes that at least one of the sensor devices be an optoelectronic sensor device, as is used, for example, in the SPACE MOUSE (trademark).
In order to make it easier for the user to keep his balance on the CYBERSURFER and also to be able to limit the maximum angle of tilt of the support plate to a relatively small value of, for example, 10xc2x0 to 15xc2x0, the provision of a restoring device which opposes tilting of the support surface is proposed. This restoring device may be provided at a low cost if is comprises at least one compressible element, preferably at least one element filled with a compressible medium, for example a pressure hose. The compressible element may act on the intermediate part, for example.
It may also be advantageous with respect to the rotational mounting arrangement to provide a restoring device which opposes a turning movement of the support surface, which device can be provided simply and at a low cost by including at least one elastic, preferably elastomeric or spring-elastic element which is articulated at one end to the support plate and at the other to the intermediate part.
If the support surface undergoes a rotational deflection due to the upper part of the user""s body rotating relative to his legs, i.e. a movement as is executed, for example, when the walking direction is to be changed, the rotational restoring device ensures that the support surface and thus also the body of the user is returned to an initial rotational position. A friction or damping device may additionally be associated with the rotational mounting arrangement to prevent this return movement from taking place too quickly and preferably make it imperceptible, or almost so, to the user.
This return to the initial rotational position is also important with regard to the safety of the user standing on the CYPERSURFER, as the latter can always be sure of retaining substantially the same relative orientation in real space. If, for example, handles or similar are disposed at the user""s side, the latter knows that, should he accidentally lose his balance, he only need reach beside him to regain his balance with the aid of the handles. He can therefore be sure that the handles are at his side and not, for example, in front of or behind him.
It is also possible to provide a vertical restoring device which opposes a vertical movement of the support surface, especially in case the direction of a vertical movement of the user is also to be detected. This device may include at least one compressible element, for example. If at least one element filled with a compressible medium, for example a compressed-air hose, is used, this may at the same time adopt the tilting and vertical restoring position. If it is only the detection of the magnitude of a vertical movement of the user which is of interest, the restoring action can be accomplished by the weight of the user himself after the support surface has been relieved of the load.
In order to enable the CYBERSURFER according to the invention to be adapted to being used by both a child and an adult, it is proposed that the restoring force of at least one of the restoring devices be variable. As the forces or torques which a child can exert on the support surface of the CYBERSURFER are usually considerably smaller, it should be possible to reduce the restoring forces accordingly when the CYBERSURFER is used by a child.
If the restoring device includes an element filled with a compressible medium, for example a gas-filled hose, the restoring force can be increased or reduced by raising or lowering the gas pressure in the hose. However if the restoring device includes elastic elements, e.g. helical tension springs, a variable restoring force can be achieved by forming one of the articulation points of thexe2x80x94at least onexe2x80x94elastic element at a slide which can be displaced on a screw spindle, the screw spindle being rotatably retained at the respective element, support surface or bearing part.
In order to be able to offer the user a relatively stable initial support surface position, from which the support surface is not deflected each time the user shifts his weight slightly (with a corresponding result for the movement of the virtual body in virtual space), it is proposed that a detent device be provided which only allows the support surface to tilt out of an initial position upon a tilting moment which exceeds a predetermined tilting moment being exerted on this support surface. A detent device which only allows the support surface to turn upon a torque which exceeds a predetermined torque being exerted on this support surface may also be associated with the rotational bearing. Finally, it is of advantage also to provide a vertical detent device which only allows the support surface to execute a vertical movement upon an impulse which exceeds a predetermined impulse being exerted on this support surface.
At least one of the above-mentioned detent devices may include a detent pin at the support unit or the base part, as well as an associated detent depression at the base part or support unit, the detent pin preferably being preloaded by a spring into the detent depression. If at least three detent pins are provided which each co-operate with a detent depression extending in a substantially vertical direction over a predetermined length or with a detent point, these may undertake both the tilt locking action and the rotational locking action and, when using detent points instead of elongate detent depressions, even the vertical locking action. The preloading force for the locking action may of course be adjustable.
Both with regard to the safety of the user and with regard to protecting the CYBERSURFER, and in particular its sensor device, against damage, in a development of the invention, it is proposed that an angle of tilt limiting device and/or a rotational angle limiting device and/or a vertical movement limiting device be provided, each of these limiting devices including at least one stop surface and at least one associated mating stop surface.
It is also proposed that the initial position of the bearing device relative to the foundation be variable or adjustable. It is thereby possible, for example, to prevent a user who is standing on the bearing device from feeling as though he were walking down a slope if the support surface tilts, as is required to bring about a forward movement at a pleasant speed in virtual space.
In order to be able to increase the user""s stability on the support surface, particularly with regard to his safety, it is proposed that the support surface comprise a non-slip surface coating. At least one retaining loop or tie for a foot of the user may be provided on the support surface as an additional or alternative measure.
For certain applications it may be of advantage for the CYBERSURFER according to the invention to comprise at least one connection for a further device for detecting movements of the user, for example for a cyber-glove, and/or at least one connection for a visual and/or acoustic output unit. Possible visual output units, apart from a cyber-helmet, are monitors and projection devices, for example large-area laser projectors. Both groups of features, which can be used together or alternatively, help to augment the impression of virtual reality.
With a view to the possibility of using the CYBERSURFER according to the invention for as many purposes as possible, it is also proposed that a standardized interface for a data processing system, for example a standardized serial or parallel interface, be associated with at least one of the connections, which interface may also be a standardized, so-called game port.
According to a further aspect, the invention relates to a method for controlling the movement of a body virtually present in a data processing system in a correspondingly virtual space on the basis of the states of movement of the real body of a user which are detected by a device according to the invention, in which method according to the invention different movement parameters of the virtual body are controlled on the basis of the detected sensor signals.
These sensor signals or the underlying movements/states of movement of the real body of the user in real space may be used in different ways to control the movement of the body in virtual space.
For example, the direction of a translatory movement of the virtual body may be controlled on the basis of the detected direction of a shift of the center of gravity of the real body of the user, and the speed of a translatory movement of the virtual body controlled on the basis of the magnitude of the shift of the center of gravity of the real body of the user. Given this interpretation of the sensor signals, the shift of the body weight is therefore used solely to control a purely translatory movement of the body in virtual space.
Alternatively, the radius of curve of a circular movement of the virtual body may be controlled on the basis of the detected direction of a shift of the center of gravity of the real body of the user, and the speed of the movement of the virtual body controlled on the basis of the magnitude of the shift of the center of gravity of the real body of the user. This form of interpretation may be used, for example, to simulate a motorcycle race or similar.
Instead of controlling the speed on the basis of the magnitude of the shift of the center of gravity, the acceleration of the movement of the virtual body could alternatively also be controlled on the basis of the magnitude of the shift of the center of gravity of the real body of the user.
According to a xe2x80x9c1:1xe2x80x9d interpretation the direction of a tilting movement of the virtual body can be controlled on the basis of the detected direction of a shift of the center of gravity of the real body of the user, and the magnitude of the tilting movement of the virtual body controlled on the basis of the magnitude of the shift of the center of gravity of the real body of the user. This interpretation is of advantage, for example, when simulating surf-riding or surfing. The above-mentioned safety handles may perform an additional function when the sensor signals are thus interpreted. For when simulating wind-surfing, the user can grip the handle as a simulation of the trapeze of the wind-surf sail. When simulating surf-riding, snowboarding or similar, the user can take up an inclined position, as would be required in reality to balance the dynamic forces occurring, with the aid of the handle.
According to another interpretation the speed or the acceleration of a movement of the virtual body can be controlled on the basis of the magnitude of a forward shift, determined from the direction and magnitude of the shift of the center of gravity, of the real body of the user, and the radius of curve of a circular movement of the virtual body controlled on the basis of the magnitude of a lateral shift, determined from the direction and magnitude of the shift of the center of gravity, of the real body of the user.
It is also possible to control a rotation of the virtual body about its transverse axis on the basis of the magnitude of a forward shift, determined from the direction and magnitude of the shift of the center of gravity, of the real body of the user, and control a rotation of the virtual body about its longitudinal axis or/and vertical axis on the basis of the magnitude of a lateral shift, determined from the direction and magnitude of the shift of the center of gravity, of the real body of the user.
The above-mentioned various interpretation possibilities for the movement of the support surface, resulting from a shift of the body weight of the user, may also include the control of the direction and magnitude of a rotation of the virtual body about its vertical axis on the basis of the detected direction or the detected magnitude of a rotational movement of the real body of the user or/and the control of the direction and magnitude of a movement of the virtual body in the direction of its vertical axis on the basis of the detected direction or the detected magnitude of the impulse transmission as a result of a vertical movement of the real body of the user.
The invention also provides for a method of simulating an activity of a user which includes at least partially supporting the user on a support surface of a support plate which is rotatable relative to a base structure, detecting movements of the support plate by way of a sensor device mounted to the base structure, resisting rotational movement of the support plate relative to an intermediate plate by way of an adjustable rotation biasing device disposed between the support plate and the intermediate plate, resisting a tilting of the support plate by way of a detent device, resisting tilting of the support plate by way of an adjustable tilt restoring device disposed between the base structure and the intermediate plate, and placing the user on the support surface, wherein the support part is rotatable and tiltable about an axis when the user is placed on the support surface.
Although the device according to the invention and the method according to the invention were illustrated above on the basis of the control of the locomotion of the virtual body of the user in virtual space, the virtual body may of course also be any other virtual object, for example an object which is designed by means of a CAD program and the position of which in virtual space is to be varied.